Browse by Author: Brian Whipker
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Phosphorus (P) deficiency in tobacco begins as a noticeable stunting when compared to a plant with a sufficient supply of P. Additionally, a P deficient tobacco plant may develop a darker green coloration of the upper foliage. Lower leaves will become chlorotic with a mottling of olive green leaf spots. The initial symptoms appearing on the lower foliage may be attributed to the fact that P is mobile within plant tissues and is translocated from these older leaves to the young developing tissues under periods of low P.

Potassium (K) is one of the three core macronutrients, and consequently, deficiency symptoms manifest relatively quickly in tobacco. Potassium is a mobile element, which means it will translocate from mature tissues to the younger tissues where it is needed. This movement of K from older to younger foliage is what causes deficiency symptoms to develop first on the lower foliage.

Providing a proper nutritional program is essential for growing top quality plants. Sampling the root substrate for pH and electrical conductivity (EC) with the PourThru extraction method is a quick and simple check of the nutritional status of a crop. The PourThru extraction method allows rapid on-site determination of pH and EC values. The values provide clues about a crop’s performance before deficiency or toxicity symptoms appear.

Tobacco plants that are B deficient are stunted very early on in production when compared to healthy plants. Initial symptoms involve a noticeable distortion at the growing point. The youngest leaves will develop kinks and other unusual growth patterns. Additionally, the upper leaves will be very thick and brittle to the touch. It has a very distinct “ridged” feeling compared to healthy plants.
Symptoms can progress very quickly once initial symptoms are observed. The distorted terminal bud will quickly become necrotic and may abscise from the plant. The older foliage will often become darker green in coloration and will also become distorted. The leaves will begin to curl downward and will take on a crinkled appearance.

Calcium (Ca) is essential for proper plant development and leaf expansion. A calcium deficiency will first manifest in the youngest foliage because Ca is an immobile element within the plant. As calcium deficiency progresses, the developmental damages will also advance. The integral role of Ca in leaf development makes its early diagnosis vital to tobacco production.

Tobacco that is deficient in magnesium (Mg) will initially develop symptoms on the lower or older foliage. These symptoms occur as an interveinal chlorosis that begins on the leaf margin, typically toward the leaf tip. Mg is mobile within plant tissues and will readily translocated from older leaves to the young developing tissues during limited Mg conditions.

Manganese (Mn) deficiency begins as an interveinal chlorosis on the upper leaves. As the symptoms progress, the interveinal chlorosis takes on a white netting type appearance. With advanced symptoms, small white spots develop and over time the spots enlarge into larger white spots.

Ornamental sweetpotatoes are extremely heat-tolerant, tropical, perennial vines grown as annuals in North Carolina. They look great covering annual beds, hanging over walls or trailing from containers. This publication covers cultivars, how to select the plants, care through the growing season and pests and diseases.

Interest in growing herbs for the retail and wholesale market has increased greatly over the past few years. Growers who have had success in the production of bedding plants have found another profitable avenue in herb production. Herbs have cultural requirements similar to bedding plants and it should be easy for greenhouse growers to add herbs to their production schedule. The majority of herbs discussed in this article can be sown, transplanted, and finished by the grower. This publication will focus on the production of the “top twelve” herbs and provides general guidelines for seed propagation.

Iron (Fe) deficiency does not readily occur under field conditions. To better catalog this deficiency, we induced Fe stress under a controlled greenhouse study.
In NC State University trials, interveinal chlorosis (yellowing) developed on the youngest leaves. Over time the chlorotic areas became more pronounced.

Boron (B) is an essential element that frequently exhibits deficiency symptoms if it is in limited supply. Growers often apply additional B to avoid deficiencies, but if too much B is applied, there is the risk of B toxicity symptoms developing.
Boron toxicities initially appear on the lower, older leaves. Early symptoms of boron toxicity will appear as wrinkling of the lower leaves and interveinal chlorosis along the leaf margin. The wrinkling is most likely caused by the lack of cell expansion when toxic levels of B are present. This wrinkling will develop across the leaf’s surface resulting in leaf deformation. Over time the interveinal chlorosis will move inward and develop over most of the leaf. Cells will rapidly die when excess B is supplied, resulting in necrotic spotting. With advanced symptomology, chlorosis and necrosis will progress up the plant to other leaves.

Zinc (Zn) deficiency has not been reported under field conditions. Most of the time, the soil will have enough micros to supplement any gaps in the chosen fertilizer plan. To present a more robust set of data, we induced zinc deficiency under controlled greenhouse studies for accurate diagnosis if the problem should arise.
In NC State University trials, ornamental tobacco developed a silver cast to the leaves as the initial symptom of zinc deficiency.

Molybdenum (Mo) deficiency has not been reported under field conditions.
(Descriptions based on the book, Hunger Signs of Crops, 3rd Edition, edited by H.B. Sprague.) Under controlled greenhouse conditions, tobacco plants are slightly stunted when Mo is limited. The lower foliage of the plant develops a chlorosis, initially as a pale green, then the spots progress to a necrosis. The leaves may be crinkled and become bent or twisted.

Ethylene is an odorless, colorless gas which acts as a plant hormone. Thus it can be a growth regulator or a harmful pollutant of horticultural crops. Major losses caused by the “death hormone” can occur with high value crops such as greenhouse-grown potted plants and cut flowers, and fresh fruit and vegetables. Economic losses to greenhouse growers from ethylene pollution are reported each year and many more probably occur, but are not correctly diagnosed. This leaflet discusses ethylene sources and symptoms of damage, and how to prevent them

Copper (Cu) deficiency is extremely rare, consequently it is not normally seen in field conditions. To help with the diagnosis and treatment of Cu deficiency, we induced Cu stress under controlled greenhouse studies.
In NC State University trials, symptoms first developed in the middle part of the plant. The middle region of the leaf developed brown veins, which quickly turned black. The tissue surrounding the veins became chlorotic. Symptoms progress up the plant to the younger leaves.

In this Brassica carinata (Ethiopian mustard) update, we highlight the symptoms of nitrogen deficiency. These images are part of a project by the Southeast Partnership for Advanced Renewables from Carinata (SPARC) to develop a diagnostic series for the identification of nutrient disorders of Carinata. Carinata is an exciting new crop used for a wide variety of primary and secondary agricultural products including cover crops, feed stock, high protein meal, and rocket jet fuel. It is similar in management to Canola given both Canola and Carinata are winter annual Brassica oilseed crops.

Ornamental cabbage and kale have become increasingly popular as fall crops because they have colorful, long lasting foliage. They will often remain colorful until temperatures drop and are well suited to areas of the Southern United States which have mild winters. Ornamental cabbage and kale are also excellent complements to garden chrysanthemums and fall pansies, and will help increase overall sales.

Ornamental cabbage and kale have been the traditional ornamental vegetables for providing colorful and attractive foliage during the fall and winter months. Recently leafy vegetables, in particular oriental mustards, have become popular for landscape plantings during the cool season. Leafy vegetables which have been popular in salads and stir-fry dishes are now being adopted by curators of botanical gardens and landscape contractors as specimen plants, border plants, and in mass plantings. Planted with pansies and garden mums, these vegetables offer a change of texture and foliar color.

Poinsettias are the traditional Christmas plant because of their colorful bracts. The bracts are actually modified leaves and the yellow cyathia in the center of the bracts are the true flowers. Plant breeders have introduced many new cultivars over the past few years and there are more than 100 cultivars currently available. The array of colors range from red, pink, white, salmon, to bicolors. With these new, longer lasting cultivars being available, it is possible for a properly cared for poinsettia to remain beautiful in the home for 2 to 3 months.

Proper nutrition is essential for producing quality pansies. Pansies make a large contribution to the net profit of many greenhouse operations and should be included in a nutritional monitoring program. Sampling the root substrate pH and electrical conductivity (EC) with the PourThru extraction method is a quick and simple check of the crop’s nutritional status.

The poinsettia is a staple in greenhouse floriculture production. As the top selling potted flowering crop, successful poinsettia production is a must. Proper fertility is essential for quality plants. Monitoring and managing the root substrate pH and electrical conductivity (EC) is critical for proper poinsettia nutrition.

Most garden asters are cultivated varieties of the fall-blooming wildflower, Aster novi-belgii, or Michaelmas daisy. They are native to the United States and can be seen blooming along roadsides during the fall. From the wild types, Danish breeders have selected for new colors and compact shape. As a floriculture crop, they can be grown for cut flowers, an indoor pot crop in four-inch or 6-inch pots, or an outdoor perennial in 6-inch pots or larger. This leaflet covers the commercial production requirements for perennial garden asters.

The North Carolina State University (NCSU) Plant Disease and Insect Clinic offers a service for testing ethylene. This leaflet describes the sampling procedures to follow and fees for submitting ethylene pollution samples. (For more details about ethylene pollution in the greenhouse, consult HIL #530, entitled Ethylene: Sources, Symptoms, and Prevention for Greenhouse Crops .) This service is designed to test ethylene levels in greenhouses and is available to any greenhouse grower.

Many greenhouse-grown floricultural crops tend to grow taller than desired and require height control measures to prevent excessive internodal elongation. This leaflet is designed to introduce commercial growers to the alternatives available for height control and suggest appropriate methods for different situations.

Plant growth regulators (PGRs) are chemicals used on a wide range of floricultural crops. This publication was designed to help growers understand how and when to use PGRs in greenhouse floriculture operations.

This publication offers a selected list of labs specializing in testing and analyzing samples of greenhouse root substrate, irrigation water, fertilizer solution and plant tissue. Providing the proper nutrition program for your plants is important for controlling growth.

Annual sunflower is a native of North America with an original range from the Great Plains to the West Coast. Pot sunflowers have been popular in Europe for a number of years. Pot sunflowers are a quick crop to produce and offer an opportunity for growers to capitalize on the current consumer demand for the plant.

Proper nutrition is essential for growing top quality geraniums. Sampling the root substrate for pH and electrical conductivity (EC) with the PourThru extraction method is a quick and simple check of the nutritional status of the crop and can provide immediate clues about a crop’s performance before deficiency or toxicity symptoms appear.